The hyperbenthos is a term applied to the association of small animals living in the water layer close to the sea bed. The species composition of the hyperbenthos is distinctly different from that of other benthic and planktonic groupings, and includes endemic species, planktonic species derived from their downward extensions (often with seasonal periodicity) and endo- or epibenthic species as they emerge into the water column (usually in diel cycles). In nearly all marine ecosystems investigated to date, there is a general increase in the biomass at the benthic boundary layer (hyperbenthon) relative to the water column immediately above it, yet the zone and its fauna remain relatively poorly studied. Sampling these often highly mobile animals is not easy as they are not collected efficiently by conventional benthic or pelagic samplers. A plethora of hyperbenthic sampling devices has been constructed and used with varying success. Typically, soft-bottom communities are sampled with sledges and hard substrata (including coral reefs) with traps. In recent years, there have been considerable development in hyperbenthic research in the tropics (mostly coral reef lagoons), in temperate to cold-water coastal and shelf regions, and in the deep sea. Unfortunately, there is little or no mutual acknowledgement of results due partly to differences in terminology. For example, "hyperbenthos" and "suprabenthos" are used mainly in temperate and northern areas, whereas "demersal zooplankton" and "benthopelagic plankton" are preferred to designate the same fauna in tropical areas and the deep sea respectively. Semantic agreement is needed to enable more progress in understanding the role played by this group of animals in ecosystem functioning. The aims of this review are to summarize the disparate literature on the hyperbenthos, to bring some order to the terminology associated with this group and to stimulate more interest for this fauna.